To prepare a shipping container for transporting bulky and heavy goods, the goods should be conveyed or hoisted into containers and then firmly fixed. “U.S. Pat. No. 4,976,365—Pallet and container integrated with pallet” discloses a removable pallet with bottom rollers. According to the patent, we can first convey and fix goods or packing containers to the pallet firstly, push the pallet into shipping container and then firmly lock the pallet and the container. The international patent—“PCT/CN2011/077352—container built-in movable pallet” I applied for, discloses a guide roller structure set on the sides and front edge corners of pallet as well as snap structured locking device set in the rear edge corners of pallet. The guide roller structure may prevent damage or even laceration to the container wall, thus effectively protect the container. In addition, it has features of high strength, flexible rolling and ability to bear great impact. Simply by tightening the tightening handle, the locking device may achieve firm tightening effect. Thus, operation is rather easy and the locking effect is highly reliable.
The dimensions of current common shipping containers that meet international standard are 40 feet in length and 88 feet (2235 mm) in width. However, in North America, in addition to using the size of containers, containers of 45 feet (2235 mm wide), 48 feet (2550 mm wide) and 53 wide feet (2550 mm) are also widely used as land transportation containers suitable for highway and railway transportation. Therefore, the built-in movable pallet manufactured for standard shipping containers cannot be used in these land transportation containers of non-uniform dimensions as no effective positioning and locking can be performed.